Abstract

Internet-delivered self-help programmes with added therapist guidance have
shown efficacy in social anxiety disorder, but unguided self-help has been
insufficiently studied.

Aims

To evaluate the efficacy of guided and unguided self-help for social
anxiety disorder.

Method

Participants followed a cognitive–behavioural self-help programme in
the form of either pure bibliotherapy or an internet-based treatment with
therapist guidance and online group discussions. A subsequent trial was
conducted to evaluate treatment specificity. Participants (n = 235)
were randomised to one of three conditions in the first trial, or one of four
conditions in the second.

Results

Pure bibliotherapy and the internet-based treatment were better than
waiting list on measures of social anxiety, general anxiety, depression and
quality of life. The internet-based therapy had the highest effect sizes, but
directly comparable effects were noted for bibliotherapy augmented with online
group discussions. Gains were well maintained a year later.

Conclusions

Unguided self-help through bibliotherapy can produce enduring improvement
for individuals with social anxiety disorder.

Internet-delivered cognitive–behavioural therapy (CBT) has developed
rapidly, and emerging evidence suggests that text-based self-help manuals
presented via the internet and supported by therapist feedback can yield
reliable improvements in a variety of mental
disorders.1,2
Apart from reducing costs for office locations, travel and staff,
internet-based treatments may be of great value for people living in remote
areas, for those with irregular or inconvenient work schedules, and for
individuals who fear or cannot afford face-to-face therapy. In Sweden we have
previously developed and tested the effects of internet-delivered treatment
for social anxiety disorder (social phobia); results from one open trial and
three randomised controlled trials indicate short-term and long-term effects
that are in line with CBT delivered in the traditional
manner.3–8
This has been replicated in
Australia.9–11
A crucial question, however, is how the treatment would work when presented as
pure bibliotherapy, i.e. as a self-help book without additional therapist
guidance. Two recent studies showed only limited efficacy of pure self-help
for social anxiety
disorder,11,12
although this form of treatment has been successful for other
disorders.13 There
may be other ways to provide support in bibliotherapy, for example by using
online discussion groups. The main objective of our study was to evaluate the
efficacy of pure bibliotherapy compared with a multimodal, internet-delivered
cognitive–behavioural therapy (ICBT) package and a waiting-list control
condition. To test the robustness and specificity of the treatments, a
subsequent trial was performed that included two additional treatment arms:
bibliotherapy augmented with an online discussion group and internet-delivered
applied relaxation.

Method

Recruitment and participants

The general procedure was similar to our previous randomised controlled
trials of internet-delivered self-help for social anxiety
disorder.4–6
Participants were recruited by media advertisements and internet links from
the Swedish National Anxiety Association and the Swedish Association for
Behaviour Therapy during the spring and autumn of 2005. A web page was created
which included an outline of the study as well as general information about
social anxiety disorder, CBT, ethical issues, internet security and a
description of the study personnel. Participants filled out an application
form and a computerised screening battery consisting of the Social Phobia
Screening Questionnaire
(SPSQ),14 the
self-rated version of the Montgomery &Åsberg Depression Rating Scale
(MADRS–S),15
and additional questions regarding current and past treatment. To be included,
participants had to meet the following criteria:

a DSM–IV diagnosis of social anxiety
disorder,16
according to the SPSQ;

scoring below 31 on the MADRS–S depression scale and below 4 on the
suicide item of this scale (to prevent the inclusion of individuals in strong
need of specialist consultation);

not undergoing any other psychological treatment during the study
period;

if prescribed drugs for anxiety or depression, the dosage had to be
constant for 3 months before the treatment onset and kept constant throughout
the study;

being at least 18 years old;

living in Sweden;

having access to a computer with internet connection;

not admitting another serious or dominant disorder (e.g. psychosis,
substance misuse) that could be expected to influence the outcome of the
study;

having a primary diagnosis of social anxiety disorder according to the
Structured Clinical Interview for DSM–IV Axis I Disorders
(SCID–I).17

The last criterion was evaluated by a telephone interview in which the
diagnostic questions from the social anxiety disorder section of the
SCID–I were posed. When a person failed to meet the inclusion criteria,
an individual letter was sent with advice on where to seek more appropriate
help.

Of the 580 individuals who applied to participate, 235 individuals meeting
all inclusion criteria were eventually randomised to one of three arms in
trial 1 (ICBT, bibliotherapy alone or waiting list) or one of four arms (ICBT,
bibliotherapy alone, bibliotherapy with discussion group or internet-delivered
applied relaxation) in trial 2 (Fig.
1). Randomisation was performed by an independent third party
using an online true random-number service
(www.random.org).
Two participants, one each from the pure bibliotherapy and waiting-list
groups, withdrew immediately after randomisation because of personal reasons
and one additional participant (ICBT group) did not provide post-treatment
data. The waiting-list control group received delayed treatment after 9 weeks
(see below) but 3 individuals withdrew shortly before this treatment began.
One-year follow-up data were not provided by 34 participants (14.5%). For all
randomised participants, missing data were replaced by the last obtained score
(pre- or post-treatment), i.e. last observation carried forward.

Ten participants (4.3%) withdrew from the study after the first (n
= 6) or second (n = 4) treatment week, the main reasons being lack of
time or motivation and personal problems unrelated to the treatment. In
accordance with the intention-to-treat principle, all participants were asked
to complete post-treatment and follow-up assessments, regardless of how many
treatment modules they had completed.

The trials were approved by the regional ethics committee and written
informed consent was obtained from all participants.

Outcome measures

Four social anxiety questionnaires were used as primary outcome measures:
the Liebowitz Social Anxiety Scale self-report version
(LSAS–SR),18
the Social Phobia Scale
(SPS),19 the Social
Interaction Anxiety Scale
(SIAS)19 and the
SPSQ. In addition, three secondary measures were used to measure general
anxiety, depression and quality of life: the Beck Anxiety Inventory
(BAI),20 the
MADRS–S and the Quality of Life Inventory
(QoLI).21 All
instruments were administered via the internet before treatment (baseline),
immediately after treatment and 1 year later. Adequate psychometric properties
have previously been demonstrated for internet-administered
questionnaires.22
In addition, all participants completed the LSAS–SR online every week
(on Sundays) in order to monitor weekly treatment gains. In cases of missing
data, a brief, neutral reminder was sent 24 h later by email, and if necessary
followed by another reminder sent as an autogenerated short text message (SMS)
to the person’s mobile telephone (cellphone). The response rate on these
weekly assessments ranged between 80% and 100% across modules, and the last
available LSAS–SR rating was used to replace missing data.

Treatment credibility ratings

After the first week of treatment, i.e. after the rationale had been
presented briefly in the manual, participants answered five questions online
regarding their perceptions of the credibility of the treatment to which they
had been randomised, for example their overall belief in the treatment method
and expectancies of
improvement.23 The
total scores ranged between 5 and 50.

General treatment procedure

All participants were required to have access to a computer with an
internet connection, an email program and the ability to print out files in
pdf format. Participants were advised to use a free online email service that
automatically encrypts messages in 2048 bits.

Self-help manual

The main treatment component was our previously evaluated self-help manual
for social anxiety disorder, which consisted of 186 pages divided into nine
chapters (modules) adapted for use over the
internet.3–6
The introductory module described social anxiety disorder and facts about CBT.
Modules 2–4 described a cognitive model for social anxiety disorder and
introduced cognitive restructuring. Modules 5–7 introduced exposure
exercises and attention training. Modules 8 and 9 mainly concerned social
skills and relapse prevention. The manual was released as a self-help book for
the Swedish market after completion of the
study.24

Participants were asked to complete one module every week, i.e. a 9-week
treatment period was required. Each module consisted of information and
exercises (homework assignments) and ended with a short quiz to check
adherence. Participants were also asked to summarise, in their own words, a
central section of the module in question and to describe the outcome of the
exercises in a treatment diary (bibliotherapy groups) or in weekly email
correspondence with their internet therapist (ICBT groups). The applied
relaxation group used another manual but with a similar structure (see
below).

Discussion group

Participants in all groups except the pure bibliotherapy and waiting-list
groups had access to an online discussion forum. For each module, participants
were asked to post at least one message about a topic related to the module
and to share their weekly achievements with the rest of the group. They were
also encouraged to provide feedback and support for others. Separate
discussion groups were used for each treatment arm. Discussions were surveyed
but the study personnel did not take part in them. The discussion group was
open during the whole study period from the first day of treatment until the
1-year follow-up assessment, although the activity was very low after the
initial 9 weeks.

Internet therapists

The ICBT and IAR groups had access to an internet therapist during the
9-week treatment period. Email correspondence occurred weekly (Sundays) and
generally concerned the results of homework assignments as described in the
self-help manual. The rationale behind the homework assignments was to promote
learning and enable the internet therapists to decide whether the participants
had assimilated the information and completed their exercises. In general,
therapist feedback on the homework assignment was given within 24 h after the
participants had sent their answers by email. When the homework was completed,
the next module was made accessible. Alternatively, instruction on what needed
to be completed to proceed to the next module was sent to the participant. On
average, internet therapists spent approximately 15 min per week giving email
feedback to each participant. There were 13 internet therapists in the study,
of whom 6 were licensed clinical psychologists and 7 were clinical psychology
students in their last semester of the 5-year master’s degree programme.
The students had clinical supervision during the trial. Participants were
randomly allocated to their therapist.

Treatment arms

Internet-delivered cognitive–behavioural treatment

The ICBT package consisted of our standard internet treatment for social
anxiety
disorder.3–6
Main components were the self-help manual, weekly email feedback from an
internet therapist and an online discussion forum. Additional group exposure
sessions, as evaluated in previous
trials,4,6
were not used. Modules in the self-help manual, including practice sheets and
weekly interactive multiple choice quizzes, were presented on the web. Modules
were also sent by post on a weekly basis to the participants.

Pure bibliotherapy

Participants in the ‘pure’ bibliotherapy (Bib) arm received the
complete self-help manual for social anxiety disorder by
mail,23 together
with an explanatory letter with instructions to complete one module per week
and to fill out the LSAS–SR form online. The manual was thus the same as
the one used for ICBT with only minimal changes to the text regarding homework
assignments. For example, participants summarised the outcome of the homework
assignments in a treatment diary and not in emails to a therapist.
Participants had no contact with the study team except for the usual online
assessments before, immediately after and 1 year after treatment. As in all
groups, some participants received neutral reminders, sent by email or SMS, to
complete the LSAS–SR.

Waiting-list control

The waiting-list control (WLC) group controlled for time and repeated
assessments during the initial 9-week period. Participants had no contact with
each other or with the study team during their waiting period except for
conditional reminders by email or SMS to complete the weekly assessment of the
LSAS–SR. Directly after the waiting period, they were treated using the
same internet-delivered self-help manual as for the ICBT group. However,
therapist feedback was provided either in small online discussion groups or in
individual emails without access to a discussion group. One-year follow-up
assessments in the WLC group reflect the long-term effects of this
treatment.

Bibliotherapy with access to an online discussion group

The only difference in the bibliotherapy with access to an online
discussion group (BibDG) compared with ‘pure’ bibliotherapy was
accessibility to an online discussion forum (see above).

Internet-delivered applied relaxation

Participants in the internet-delivered applied relaxation (IAR) group
followed an applied relaxation
manual,25 which had
been adapted for self-help use via the internet and evaluated (e.g. for panic
disorder).26 The
manual was slightly modified to suit the population with social anxiety
disorder. The structure of the manual was the same as in the ICBT and Bib
groups, i.e. the text was divided into nine modules containing information and
exercises, and participants completed one module per week. The introductory
module included information about social anxiety disorder and anxiety
reactions. A more thorough rationale for applied relaxation was given in
module 2, i.e. a theoretical background was presented describing the
importance of noticing and preventing anxiety in its early phase. Modules
3–7 included relaxation exercises (progressive, conditioned,
differential and quick relaxation) in which participants gradually learned to
relax, with the ultimate goal of achieving a relaxed state within 20–30
s. Modules 8 and 9 included applied relaxation exercises in actual phobic
situations (in vivo exposure) and relapse prevention. Each module
ended with a quiz and homework assignments to be reported to the internet
therapist. As in the ICBT groups, participants had access to an online
discussion forum and received weekly feedback from their internet therapist,
usually within 24 h. Modules were made accessible one by one on the web, and
for convenience were also sent by post to the participants on a weekly basis
provided that homework assignments had been completed. A compact disc with
relaxation instructions was also sent to the participants.

Statistical analysis

Differential outcomes were evaluated at post-treatment and follow-up by
analysis of covariance (ANCOVA) using pre-treatment values as the covariate.
Within-group t-tests were used to evaluate additional improvement
from post-treatment to follow-up. Effect sizes were calculated based on the
pooled standard deviation (pre- and post-treatment) and expressed as
Cohen’s
d.27
Weekly treatment gains were evaluated using repeated-measurement analysis of
variance (ANOVA) and Pearson correlations were calculated to evaluate the
association between number of modules completed and level of improvement.
Clinically significant improvement was determined in accordance with Jacobson & Truax
criteria,28 i.e. by
using the Reliable Change Index for each individual and a post-treatment score
within two standard deviations of the mean of the normal population. Swedish
normative data were used for the SPSQ, SPS and SIAS
questionnaires,14,29
and American norms for the
LSAS–SR.30
Chi-squared or exact cellwise tests were used to test distribution differences
with regard to clinically significant improvement and demographic and
descriptive characteristics. Analyses were done using SPSS version 17.0 for
Windows.

At baseline, groups scored approximately three standard deviations higher
than the Swedish normal
population14,29
on the SPSQ and approximately four standard deviations higher on the SPS and
SIAS measures, indicating that participants had clinically significant
symptoms of social anxiety disorder.

Treatment effects in trial 1

Analyses of covariance for post-treatment change, using baseline values as
covariates, revealed significant main effects of the group factor
(ICBT/Bib/WLC) on all primary (F = 11.78–18.03, d.f. = 2,116,
P<0.0001) and secondary (F = 4.98–11.11, d.f. =
2,116, P<0.009) outcome measures, indicating differential
improvement over the treatment period. Bonferroni-corrected pairwise
comparisons showed that both the ICBT and the Bib groups were significantly
more improved in comparison with waiting-list controls on all social anxiety
measures (P<0.001) as well as on the BAI (P≤0.015),
MADRS–S (P≤0.001) and QoLI (P≤0.026). The ICBT
and Bib groups did not differ significantly on any measure
(P>0.10). At follow-up 1 year after all participants had received
treatment, the group factor was significant only for the SPS (F =
3.16, d.f. = 2,116, P<0.05) with pairwise comparisons indicating a
trend for better improvement in ICBT compared with Bib (P = 0.065).
All other pairwise comparisons remained insignificant at this time.

Within-group effect sizes are given in
Table 2 for primary measures
and in online Table DS1 for secondary measures. For social anxiety measures,
effect sizes in the treated groups were 0.65–1.29 post-treatment and
0.75–1.71 at follow-up relative to baseline, ICBT being associated with
the highest effects. Mean within-group effect sizes across all measures, at
post-treatment/follow-up relative to baseline were 0.82/1.07 (ICBT) and
0.64/0.76 (Bib). A mean within-group effect size of 0.61 was noted in the WLC
condition at follow-up relative to the post-treatment test, i.e. after delayed
treatment. Between-group effect sizes post-treatment, averaged across all
measures, were 0.63 for ICBT v. WLC and 0.64 for Bib v.
WLC.

Treatment effects in trial 2

Differential improvement could not be demonstrated because the ANCOVAs did
not reveal significant effects of treatment group (ICBT/Bib/BibDG/IAR) on any
post-treatment (F = 0.18–1.36, d.f. = 3,110, P =
0.91–0.26) or 1-year follow-up (F = 0.05–1.43, d.f. =
3,110, P = 0.98–0.24) measurement, and all planned group
comparisons remained insignificant (P>0.10). Within-group
evaluations showed significant improvement in all groups from pre- to
post-treatment (P<0.05 on every measure), but no group showed
additional improvement between post-treatment and follow-up (t =
1.49, d.f. = 27–28, P>0.14). Within-group effect sizes for
change in primary outcomes were 0.65–1.63 at post-treatment and
0.65–1.58 at follow-up relative to baseline, the highest effects being
observed in BibDG participants (Table
2). At least moderate effect sizes were noted for changes in
general anxiety and depression (online Table DS1), but as in trial 1, effect
sizes for changes in QoLI scores were somewhat lower. Mean effect sizes across
all measures, at post-treatment/follow-up relative to baseline were as
follows: 0.99/0.98 (ICBT), 0.74/0.75 (Bib), 0.99/1.06 (BibDG), and 0.77/0.84
(IAR).

Pooled analyses and time course of improvement

Because the relative efficacy of ICBT v. Bib was our principal
research question, data from trials 1 and 2 were pooled in order to increase
sample sizes (to n = 69 in each group) and thus the statistical
power. Data pooling was also motivated by the fact that neither the ICBT nor
the Bib arm showed significant differences across trials with regard to
primary, secondary or descriptive measures before treatment.

In ANCOVAs for post-treatment change on social anxiety measures, relative
to baseline, the group factor (ICBT/Bib) remained insignificant (F =
0.02–0.64, d.f. = 1,135, P = 0.88–0.43), indicating
similar levels of short-term improvement with the two types of treatment. The
corresponding analyses of change between baseline and 1-year follow-up
revealed a significant effect of group on the SPS (F = 4.41, d.f. =
1,135, P = 0.038) and LSAS–SR (F = 4.41, d.f. = 1,135,
P = 0.038), and a marginal effect on the SIAS (F = 3.75,
d.f. = 1,135, P = 0.055). The adjusted means of these measures
indicated better long-term improvement in the pooled ICBT group. Only
ICBTpooled improved significantly from post-treatment test to
1-year follow-up, and on primary measures only (t = 2.52–4.02,
d.f. = 68, P = 0.014–0.0001). The ICBTpooled and
Bibpooled groups could not be differentiated with regard to change
in secondary measures at either post-treatment or follow-up (F =
0.04–0.63, d.f. = 1,135, P = 0.98–0.43). Mean
within-group effect sizes across all measures at post-treatment/follow-up were
0.88/1.03 for ICBTpooled and 0.68/0.75 for Bibpooled.
Mean between-group effect sizes for ICBTpooledv.
Bibpooled were 0.09 at post-treatment and 0.16 at follow-up.

Figure 2 shows weekly
changes in LSAS–SR scores in the pooled ICBT and Bib groups in relation
to the other conditions. Repeated-measurement ANOVA yielded a significant
effect of time (F = 90.67, d.f. = 11,1496, P<0.0001) and
a tendency for a time×group (ICBTpooled/Bibpooled)
linear trend interaction (F = 3.15, d.f. = 1,136, P =
0.078). Further Bonferroni-corrected pairwise comparisons showed that the
ICBT, Bib and BibDG groups were all significantly differentiated from WLC
after the sixth week (P<0.05), whereas a tendency (P =
0.062) was observed for IAR (v. WLC) after the ninth week.

Time course of improvement on the Liebowitz Social Anxiety Scale,
self-report version (LSAS–SR). Data were recorded at screening,
immediately before treatment (week 0) and then every week until post-treatment
assessments after week 9. One-year follow-up data are also shown. Pooled data
are shown for groups treated with pure bibliotherapy (Bib) and the
internet-delivered cognitive–behavioural treatment package (ICBT). The
waiting-list control group (WLC) was treated after the initial 9-week period.
BibDG, bibliotherapy with access to an online discussion group; IAR,
internet-delivered applied relaxation.

Clinically significant improvement

The number of participants meeting the criteria for clinically significant
improvement is given in online Table DS2. The majority of participants
(59–83%) had improved on at least one social anxiety measure from
baseline to post-treatment (the WLC group excepted) and from baseline to
follow-up. In the WLC group 62% were improved after delayed treatment. The
proportion of individuals who did not improve on any measure from baseline to
follow-up was 23% in the ICBTpooled group and 30% in the
Bibpooled group. The corresponding figures in the BibDG and IAR
groups were 29% and 41%. The proportion of clinically improved/unimproved
participants did not differ across the active treatment arms at the
post-treatment test (χ2 = 2.98, d.f. = 3, P = 0.40) or
at follow-up (χ2 = 4.12, d.f. = 4, P = 0.39).

Discussion

The magnitude and time course of improvements resulting from
therapist-guided and unguided self-help programmes for social anxiety disorder
were tested in two independent randomised trials, using an intention-to-treat
model for data analyses.

Bibliotherapy with and without discussion group

Intriguingly, pure bibliotherapy had significant and reliable effects in
people with social anxiety disorder. The magnitude of improvement did not
differ significantly between the Bib and ICBT groups immediately after the
9-week treatment programme even when pooled data (i.e. more highly powered
analyses) were used, and comparable proportions met the criteria for
clinically significant improvement. However, the highest within-group effect
sizes were noted in the ICBT group. Moreover, only the ICBT group showed
evidence of further improvement from post-treatment to follow-up, and a
significant difference in favour of ICBT was noted on the LSAS–SR and
SPS a year after treatment. Gains of pure bibliotherapy were, however, well
maintained.

Although pure self-help has been shown to be efficacious in other
conditions including anxiety
disorders,13 to our
knowledge only two prior randomised controlled trials (RCTs) have examined the
efficacy of such self-help for social anxiety
disorder.11,12
In contrast to our study, only small effects of pure bibliotherapy were found
and this form of treatment was inferior to therapist-guided CBT. For example,
effect sizes for change from baseline to post-treatment on the SPS and SIAS
measures ranged between 0.28 and 0.38 respectively in participants treated
with pure
bibliotherapy,11,12
which can be compared with 0.83 and 0.65 for the Bibpooled group in
our study. As the pre-treatment values on the SPS and SIAS measures were
similar in all these studies, it is unlikely that initial differences in
symptom severity can account for differential outcomes. A difference in the
number of chapters read is also an unlikely explanatory factor because rather
modest completion rates were noted in all three studies. One possibility is
that the weekly assessments of LSAS–SR could have served as a
motivational enhancer for bibliotherapy participants in our study. However,
these assessments did not have a positive effect in the WLC group. The
dissimilar effects of pure bibliotherapy can probably be attributed to
variations in the structure and content of the written self-help programme.
Although optimisation of text-based treatment programmes is an important topic
for future research, our findings suggest that neither the pure self-help
format, nor the inclusion of individuals with severe phobia, precludes
significant treatment gains with bibliotherapy.

It could be argued that ‘real world’ bibliotherapy is inferior
to bibliotherapy within the context of an RCT. For example, individuals
purchasing a self-help book without any contact with a research team might be
less motivated to complete the written treatment programme compared with those
who participate in a clinical trial. Unfortunately it is not possible to
evaluate real world bibliotherapy properly because scientific control cannot
be achieved without assessments and at least some investigator
contact.12

Although time, assessments and contact with the study personnel were
controlled for by the waiting-list condition, the motivational factor was not.
Keeping the reader motivated is a major challenge for bibliotherapy and an
online discussion group may be one way to enhance motivation and treatment
adherence. Even though the statistical evaluation of our study did not
demonstrate significant additional gains in the bibliotherapy arm with access
to online group discussions, effect sizes were higher relative to pure
bibliotherapy and, in fact, as high as in those treated with ICBT. The number
of completed modules also tended to be higher in this arm relative to pure
bibliotherapy. However, as noted in several other self-help
studies,6,9,10
completion rates were not strongly associated with outcome, i.e. even limited
exposure to the self-help programme had beneficial effects.

Internet-delivered treatment with therapist guidance

The effect sizes for ICBT compare well with those reported in our previous
trials.4–6
Thus, short-term and long-term efficacy of internet-delivered CBT for social
anxiety disorder has now been demonstrated in five RCTs in Sweden. The
efficacy of online treatment for social anxiety disorder is also supported by
three recent trials performed in
Australia.9–11
However, studies that have evaluated text-based treatments not using the
internet as a mean of delivery have also reported significant gains in people
with social anxiety
disorder.12,31
The current data further suggest that neither the internet format nor
therapist feedback are necessary for obtaining clinical improvement because
directly comparable gains were noted in the BibDG arm lacking these
components. Interestingly, our previous trials did not demonstrate better
effects of ICBT combined with two to five group therapy
sessions,4,6
which raises questions as to the value of additional therapist-led contact, at
least in the group context. On the other hand, we found a strong association
between therapist input and effect size in another
trial,32 also seen
in a meta-analysis.2
Although more studies comparing self-help with face-to-face therapy clearly
are needed, Rapee et al reported comparable effects of augmented
self-help and standard group CBT for social anxiety
disorder.12

Specificity of the text-based treatment

Treatment specificity for the text-based self-help manual for social
anxiety disorder24
can be questioned, because participants treated with applied relaxation –
which was based on a completely different manual – also improved
to levels that were statistically indistinguishable from the other treatment
arms. At the time the study was planned, meta-analytical evidence suggested
that applied relaxation had only moderate effects, similar to pill
placebo.8 Recent
studies, however, have demonstrated that applied relaxation may be effective
for at least some people with social anxiety
disorder.33 Thus, a
variety of treatment techniques may produce significant gains in this clinical
population. It should also be noted that there was some overlap between
applied relaxation and the standard self-help programme, for example with
regard to psychoeducation and exposure exercises. Dismantling studies are
needed to determine the active components in the different self-help
programmes tested here. Comparisons with a credible placebo control are also
necessary before it can be safely concluded that the
cognitive–behavioural components are responsible for the therapeutic
effects, although meta-analyses report lower effect sizes for
placebo.8

Time course of improvement

To our knowledge, the time course of improvement has not previously been
evaluated in studies of text-based self-help programmes. This type of data can
be relevant for clinical planning and for handling low-intensity treatments.
It might be expected that the effects of CBT, being learning-based, evolve
rather slowly and progress more rapidly during the second half of the
treatment period. For example, in a clinical study of social anxiety disorder,
Heimberg et al noted that CBT was associated with fewer responders in
comparison to phenelzine midway through treatment but that the response rate
was approximately similar after the full 12-week treatment
period.34 However,
in our study both the ICBT and Bib groups improved gradually and steadily.
Intriguingly, more than half of the change at the post-treatment assessment
had already been achieved after the first 4 weeks. Comparable response curves
were noted in the other treatment arms, with the possible exception of the IAR
group. Considerable gains may thus be expected early in the self-help
treatment period, shedding light on the somewhat puzzling observation that
substantial improvement occurs even though completion rates are moderate or
low.

Limitations

Some limitations of our study require comment. First, because of moderate
sample sizes (especially in trial 2), absence of differential improvement
should be interpreted with power issues in mind. Unfortunately, we could only
use the more highly powered (pooled) analyses when comparing the ICBT and Bib
groups. Second, excluding people who were suicidal or had severe depression
might limit the generalisability of our findings. These individuals are,
however, usually considered too risky to include in research trials. Third,
differential diagnosis could be an issue because, as in our previous
trials,5,6
the telephone screening procedure did not permit in-depth psychiatric
assessment. Comorbidity analyses could thus not be performed. Fourth,
assessors were not masked with regard to the treatment assignment. However,
all assessments were conducted online with standardised written instructions
and automatic scoring, reducing the risk of reactivity or experimenter
effects. Finally, we could not control for other treatments received during
the 1-year follow-up period, which may affect interpretation of the long-term
effects.

Future directions and implications

Future studies could compare pure bibliotherapy with therapist-led group or
individual CBT and examine if the bibliotherapy format could be further
improved, for example by computer-interactive methods. This can be crucial as
unguided programmes often lead to high withdrawal rates, at least on
open-access
websites.35 Studies
could also evaluate whether bibliotherapy improves the effect of serotonin
reuptake inhibitors or other anxiolytic agents. Finally, bibliotherapy might
be evaluated in a stepped-care model in which more resource-demanding
interventions are gradually offered to those who do not respond.

In conclusion, this study replicates the positive results of
internet-delivered CBT previously demonstrated for individuals with social
anxiety disorder, and also demonstrates that bibliotherapy without therapist
input can lead to substantial long-lasting improvement, especially when
supported with an online discussion group. This may have important clinical
implications because bibliotherapy, being cheap and widely available, can be
used as an augmentation to pharmacotherapy, or as the initial intervention
before other therapies are offered.

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